Abstract

The analysis of morphological characters of the autopodium of Dragonara megacerine deer put in evidence adaptations similar to those of typical bovids living on hard grounds rather than of typical cervids living on soft grounds. Also in continental megacerine deers morphological and biometric characters are present suggesting some adaptations to walking on level and hard grounds and a relatively cursorial capability, with the possibility to keep a moderate speed also on long distances. The Dragonara megacerine deer presents lengthening of the zeugopodium and autopodium, with respect to presumed ancestor of the «group of Megaceros verticornis (Dawkins)». Nevertheless, the lengthening of metacarpal bone is smaller than that of metatarsal; thus, since the anterior limb of Cervus (Przewalskium) albirostris Przewaiskij, living in mountainous environments, is shorter than the posterior one, the Dragonara megacerine deer might be adapted to move quite swiftly on hard uneven grounds. The acquired more cursorial adaptation, that may be connected partly with size reduction, is accompained by acquisition of a more firm intercarpal, intertarsal, metapodial-phalangeal and interphalangeal joints, with reduction of lateral movements, which nevertheless results less marked than the one of mountainous or jumping forms. Most of morphological characters are present in forms with generical adaptations on hard grounds; characters of typically jumping forms are missing (tarsal joints that prevent lateral movements and excessive flexion); characters that appear in lowland forms are present (e.g. morphology of dorsal face of cuboscaphoid, height and shortness of third phalanx), and others that are proper in mountainous forms (sole of third phalaux with good defined margins). The development of retroarticular platform of the second phalanx is considerable if compared with the one of typical bovids; nevertheless it is less developed than the one of presumed ancestor, On the other hand, a certain development of the platform is present also in cervids living on hard grounds of lowland and/or mountain, eg. the mule deer (Odocoileus hemionus Pallas) and whitefaced deer. Both lowland and mountain forms are characterized by a anteriorly tapered and moderately or much restricted third phalanx sole. The sole of the Dragonara megacerine deer is relatively wide, but reduced with respect to the presumed ancestor. However, a relatively wide sole, if compared to tipical mountainous forms, characterizes also Cervus (Przewalskium) albirostris. Also if the scarcity of remains makes indicative the comparison with megacerine deers of the «group of M, verticornis», it seems that the Dragonara megacerine must be considered a peculiar form within cervids, in particular within insular ones: its metapodials are not shortened, and the mobility of tarsal bones is kept. The Dragonara megacerine deer seems adapted to walking on hard and also more or less uneven grounds, with a rather swift gait and possibility of making sharp lateral shies (ethogical signals?, presence of obstacles?) and diminishing concussion in landing when the weight comes on the hoofs. These adaptations are in accordance with geomorphomogical and paleoenvironmental data, which show for Sardinia during the penultimate glaciation the presence of relatively uneven zones, but also of rather wide coastal lowlands and moderately dry and brushy envirorìments.